Inspection mold for a multi-chamber container preform

ABSTRACT

The multi-chamber containers with a dispenser/doser are blow molded as a single integral item. They then are fitted with dip tubes with the dip tube fitment forming a seal in the transition of the container to the dispenser/doser. The dividing walls in the container are continued up into and through the dispenser/doser. A closure with a rotatable contact surface seals the container. The container preform is made by injection molding using an elongated gate pad in one embodiment in another embodiment an arrangement of recesses on the ends of the core projections with a complementary shaped gate pad. The webs of the container are of a thickness so that they flex upon a compression force being applied to the container walls.

This is a Divisional, of application Ser. No.08/310,557 filed Sep. 21,1994 and now U.S. Pat. No. 5,573,143.

FIELD OF THE INVENTION

This invention relates to blow molded multi-chamber dispensingcontainers, the methods for blow molding multi-chamber dispensingcontainers, and molds for use in making preforms and for blow moldingmulti-chamber dispensing containers. More particularly this inventionrelates to multi-chamber containers which have an ellipticalcross-section and where in dispensing the substances are kept separatethrough the point of flowing into a receptacle.

Multi-chamber containers are of two general types. A first type is wherethe chambers are separate containers which then are interfitted togetheror held together with a shrink band. A multi-chamber container of thistype is disclosed in U.S. Pat. No. 5,158,191. This patent shows twobottles held together with an interfitting arrangement. Whether thebottles are interfitted together or held together with a shrink bandthere is a lack of stability. There always will be some inter-containermovement. A preferred container is one that has multiple chambers as apart of its basic structure. The most effective way to make suchcontainers is by blow molding. However it is difficult to producemulti-chambered containers by blow molding. Techniques for blow moldingmulti-chamber containers are disclosed in Japanese Application No.11430/1968, as well as in U.S. Pat. No. 5,232,108 and U.S. Pat.No.5,242,066. Japanese Application No. 11430/1968 discloses injectionmolding a preform having a center wall and then blowing this preform toa container with two compartments. This container can be round orelliptical. U.S. Pat. No.5,232,108 discloses a round multi-chambercontainer which has been blown from a preform that has multiplechambers. This patent discloses a technique for maintaining theintegrity of the center wall during the blow molding phase. U.S. Pat.No.5,242,066 discloses plastic bottles that have internal reinforcingspiders or webs. The objective in this patent is to reinforce the wallof a bottle that is to contain a carbonated beverage. These spiders orwebs usually will not extend fully from the bottom of the bottle to thebottle exit since there is no need to keep the liquid portions separate.The liquid throughout the bottle is the same.

The preferred multi-chamber container is one that is made in one pieceand that is of an integral structure. The container costs less to makeand to fill. It also has more structural integrity. However, it isdifficult to blow mold multi-chamber containers, and in particularmulti-chamber containers which have other than a round shape. Also it isdifficult to blow mold a multi-chamber container which includes anintegral dispensing arrangement where the fluids from each chamber ofthe containers do not mix until flowed from the container into areceptacle.

The present invention overcomes the problems of the prior art anddiscloses multi-chamber dispensing and dosing containers that are of anintegral structure. These containers are blow-molded from an injectedpreform with assembly only including the insertion of delivery dip tubefitments and providing a closure. This multi-chamber container is easilyfilled and has full structural integrity during storage, handling anduse.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to multi-chamber dispensing and dosingcontainers which are of an integral one-piece construction. Themulti-chamber container is blow molded having separate multiple chamberswhich are separate from the base of the container through the dispensingand dosing section. The container is preferably elliptical and the webswhich form the chamber dividing walls have a decreased thickness in thecentral region of the web. The dispensing and dosing arrangement is anintegral part of the container structure with the dosing and dispensingportion being divided into separate chambers, the same as in thecontainer. The webs that form the separating walls in the container arecontinued into and throughout the dispenser/doser region to maintain thechambers separate throughout the container and dispenser/doser.

The chamber forming web must flex when the bottle side walls arecompressed. This flexing will be at a center region of each web where itis at its decreased thickness.

A closure for the container is threadedly engaged onto thedispenser/doser portion. The part of the closure which contacts the topsurfaces of the dispenser/doser, which includes the edge of the chamberforming webs, should preferably be rotatable with respect to theclosure. In this way the seal surface in the closure will not be damagedupon contact with the web edges.

The container includes dip tubes which are seated in the transition ofthe containment portion of the container to the dispenser/doser portion.There is a dip tube for each chamber. The lower end of each dip tube isirregular, and preferably V-shaped.

The preform to produce the multi-chamber containers will have a webstructure that is to be the web structure of the multi-chamber bottle.The preform is injection molded. The mold core is comprised of threesections for increased stability. There is the core base section and twocore projections. The base section holds the core projections that formthe multiple chambers. At a lower end of the core projections therepreferably are recesses to enhance the flow of plastic with acomplementary gate pad. The gate pad of the injection mold is of anelongated shape to further enhance the flow of plastic and to preventcore projection deflection during molding.

It is preferred that the container and consequently the blow mold havevertically oriented discontinuities in order to promote the expansionduring preform blowing only in a vertical and a horizontal directionwith no angular movement of the plastic during blowing. This willmaintain the chamber web walls in a vertical orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of the container with a closure.

FIG. 2 is a horizontal sectional view of the container of FIG. 1 withoutthe closure.

FIG. 3 is a elevational view of the dispenser/doser parts of thecontainer of FIG. 2 showing side delivery from the dip tubes.

FIG. 4 is an elevational view of the dispenser/doser part of thecontainer of FIG. 3 rotated 90 degrees.

FIG. 5 is a top plan view of the container of FIG. 2.

FIG. 6 is a view of the bottom of a dip tube.

FIG. 7 is an elevational view of the container preform.

FIG. 8 is an elevational view of the preform of FIG. 7 in a horizontalsection.

FIG. 9 is a top plan view of the preform of FIG. 7.

FIG. 10 is an elevational view of the core of the mold for the preform.

FIG. 11 is an elevational view in section of the injection mold formaking preforms.

FIG. 12 is a bottom view of the injection mold of FIG. 11 with anelongated gate pad.

FIG. 13 is an inner surface of a blow mold showing recesses andprojections to promote a vertical downward flow of plastic during blowmolding.

DETAILED DESCRIPTION OF THE INVENTION

The present container is shown in FIG. 1. Container 10 has sidewall 12,base 14 and sidewall shoulder area 16. Within the container is web 22which separates the container into two chambers. The web has a minimumthickness in the central region, that is, a region equidistant from thesidewalls. This will be a thickness of less than about 0.4 mm, andpreferably less than 0.2 mm. Each chamber has a dip tube 24, 26extending from the sidewall shoulder to near the base. On the surface ofthe bottle is a vertical projection 15 and a vertical recess 13. Theseare ornamental in the end product bottle but are used to stabilize theplastic material distribution after contact with the mold during blowmolding.

At the upper end of the bottle is locking ring 18 and closure 20.

This bottle is shown in cross-section and without the closure in FIG. 2.It is shown that each of dip tubes 24 and 26 are connected into fitment30 which also seals upper dispensing/doser chambers 31, 33 from thelower containment chambers 17, 19. Extending up from fitment 30 are diptube extensions 32 and 34. Each of these dip tube extensions has anopening 36. The dispensing/doser chambers are formed by web 22 and wall40. The exit of the dispenser/doser section in aperture 44. Threads 42attach the closure to the container. The web 22 extends from the base ofthe bottle to the dispenser/doser exit 44.

FIG. 3 shows the top dispensing/doser section of the container. In thisembodiment dip tube extensions 32 and 34 have side openings 38 fordispensing product. Lugs 46 (see also FIG. 4) are locking lugs that areused to hold the closure securely in place. In FIG. 4 the dischargeopenings 38 are shown in more detail.

FIG. 5 is a top plan view of the container showing the D-shaped fitmentsthat hold the dip tube extensions and also which seal the dip tubes inthe shoulder of bottle 10.

FIG. 6 shows the end of a dip tube with a V-shape 35. This shape willpermit a flow of liquid up the dip tube regardless of the contact of thedip tube with the sidewall or base of the container.

FIG. 7 discloses a preform for making the container of FIG. 1. Thispreform consists of a plastic tube 50 having a sidewall 52 and an innerwall 56. Wall 58 will be the outer wall of the dispenser/doser and ofthe blown container. In blowing the container the lugs 46 or the innerwall 56 can be used to align the preform in the mold. Alignment isimportant. For an elliptical bottle the blow mold will be elliptical inshape. The preform will be placed in the mold in different orientationsto produce a blown bottle with a web along the major axis, along theminor axis or at an angle to the major axis or minor axis. Since ininjection molding the preform the lugs 46 and the center wall 56 willalways be in the same locations these are useful for reference points inaligning the preform in the blow mold.

FIG. 8 is an horizontal section of the preform of FIG. 7. FIG. 9 is atop plan view of the preform.

FIG. 10 shows the core mold for making the preform. The core mold 60 iscomprised of three parts. These are core base 66 and core projections 62and 64 center void space 68 will produce the inner wall of the preform.In a preferred embodiment surfaces 70 and 72 are recessed at the lowerend to produce recesses 74 and 76. FIG. 11 shows core mold 60 in theinjection mold 80. This consists of mold body 82 and gate 84. A gate padcovers part of gate 84 and regulates the flow of plastic duringinjection molding. Injection mold 80 is vented at 67 at the top of innerwall 56. FIG. 12 shows gate pad 86 with an elongated gate aperture 84.The objective in FIG. 12 is to use a gate pad which will allow for theflow of plastic to control the deflection of the core projections duringinjection molding. It also is an objective to control any movement ofcore projections 62 and 64 and thus produce a uniform preform. Thiscontrol can also be achieved through the use of recesses 74 and 76 and agate pad with a circular aperture. This control is increased by the useof recesses 74 and 76 in combination with an elongated aperture. Apreform that is out of specification will produce a bottle that is outof specification.

FIG. 13 shows a half section 92 of a blow mold 90 with various recesses91 and 95 or protrusions 93 and 97. Section 94 forms the dispenser/doserof the container. These features will result in the opposite effect inthe blown bottle. The objective of these recesses and projections is topromote a vertical flow of plastic along the blow mold wall during theblow mold process. If the plastic does not flow vertically, but at anangle, there can result a spiraling of the inner wall 56 of the preformas the bottle is being formed.

The preform is formed by heating the plastic so that it flows andapplying a melt pressure of about 2000 to 20,000 psi. The usefulplastics include polypropylene, polyvinyl chloride,acrylonitrile-styrene or their copolymers, polyethylene terephthalate orcopolymers or terpolymers thereof, and polybutylene terephthalate. Afterbeing form the preform is placed in a blow mold and with an internal airpressure of about 100 to 1000 psi is blown to the shape of the mold.Preferably the pressure is about 600 psi.

The foregoing description describes the preferred and best mode forpracticing the present invention. Modifications to the disclosedembodiments are contemplated to produce particular containers and areconsidered to be within the scope of the present invention.

An option with regard to the dip tubes is to mold the dip tubes onto thebottle inner wall as the bottle is made and solely then to insert a pealfitment between the dispenser/doser portion. This reduces the number ofparts.

A further option is to use a telescoping stretch rod technique in blowmolding the containers. A telescoping stretch technique providesadvantages in the distribution of the air during blowing. This canproduce a container with a more uniform web.

We claim:
 1. An injection mold for a multi-chamber container preformcomprising:a. a mold body having an upper portion and a bottom portion;b. a mold core within said mold body comprised of at least a base and aplurality of separate core projections extending from said base andhaving a shape related to the shape of said multi-chamber container; c.a gate pad on said bottom portion aligned with a space between saidplurality of separate projections; and d. a gate on said gate pad, saidgate having an elongated aperture to control the flow of plastic intothe mold and to thereby control deflection of said core projectionsduring the flow of such plastic into the mold.
 2. An injection mold asin claim 1 wherein each of said projections is separated from the otherby a space that tapers inwardly from the bottom portion of said moldbody to the upper portion of said mold body.
 3. An injection mold as inclaim 1 wherein there is a greater space between said projections andsaid mold body at the bottom portion of said mold body.
 4. An injectionmold as in claim 1 wherein there are recesses on said projectionsadjacent a bottom portion of said mold body.
 5. An injection mold as inclaim 1 wherein the lesser cross-sectional dimension of said elongatedaperture is in alignment with said center void space.
 6. An injectionmold as in claim 1 wherein said gate pad has a circular aperture.